Absorbent pant diaper having friction increasing means

ABSTRACT

The present invention discloses a disposable absorbent pant or diaper having a crotch portion and front and back portions adjacent thereto which are joined to form a waist portion surrounding the waist of the user. The waist portion is circumferentially elastic around the waist of the user. At least one cover layer extends from at least the front portion to the back portion and an absorbent body is disposed adjacent to the at least one cover layer. The absorbent body is held tightly against the body of the user by the elastic waist portion. At least portions of the surface of the waist portion facing the skin of the user are provided with a friction agent to form a friction increasing surface against the skin of the user.

TECHNICAL FIELD

The present invention is directed to a disposable absorbent pant ordiaper and, more particularly, to a disposable absorbent pant or diaperhaving a waist portion with elements for increasing the frictionalresistance upon contact with the skin of the user, such that thecircumferential elastic may be reduced.

BACKGROUND OF THE INVENTION

The present invention relates to a pair of absorbent pants or a pantdiaper for one-time use, comprising a crotch portion, front and backportions adjacent thereto, which are joined to form a waist portionsurrounding the waist of the user, said portion being circumferentiallyelastic, an absorbent body, which is held tightly against the body ofthe user by the elastic waist portion. Such an absorbent pant diaper isknown by our own Swedish patent application 9200663-4, having around thewaist elastically extensible elements, for example elasticallyextensible strings, strips, film, fibre fabric, laminates or the like,which are designed to hold the pant diaper in place on the user andprevent it from slipping down from its intended position of use. Inorder to prevent the elastic tension from being uncomfortable for theuser, the known pant diaper is provided with a large number of elasticelements, which, by virtue of their number, on one hand exert asufficient total tightening force around the waist of the user for thepant diaper to not slip down, and, on the other hand, each does notexert an excessive local pressure on the user. However, the use of alarge number of elastic elements involves a relatively high materialcost. It is therefore desirable to be able to reduce the need forelastic elements in the waist portion of the pant diaper without havingto deviate from the requirement that the pant diaper should stay upcomfortably on the user.

SUMMARY OF THE INVENTION

These and other problems are solved by a disposable absorbent pantdiaper of the type described by way of introduction which ischaracterized in that at least portions of the surface of the waistportion facing the skin of the user are provided with a friction agentto form a friction increasing surface against the skin. This preventsthe pant diaper from slipping down, in a very inexpensive and simplemanner without having to use many elastic threads. This makes itpossible to supply a very limited number of pant waist sizes while stillrequiring that the pant diaper should stay in place during use. Thepresent invention can, however, also be used with advantage on a pantdiaper having a large number of elastic elements in the waist portion.In this case, it is possible to reduce the tension which the elasticelements exerts on the user, since the frictional force of the frictionagent compensates for the reduced friction resulting from the loweringof the elastic tension. It is of course possible to use the invention onother types of pant diapers as well, which do not use a large number ofelastic elements in the waist, for the purpose of improving the frictionagainst the body of the user, i.e. improving the stay-up capacity of thepant diaper.

U.S. Pat. No. 4,834,739 describes the use of friction coatings on asanitary napkin to keep the napkin in place relative to the underpantsand thighs of the wearer. This invention is, however, directed to anentirely different problem as is mentioned above and an entirelydifferent field, namely a sanitary napkin which is held up by the user'sunderpants.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described in more detail withreference to the accompanying drawings, where:

FIG. 1 shows a schematic plan view of an absorbent pant diaper accordingto one embodiment of the invention as seen towards the outside of thepant diaper in a state in which the front and back portions of the pantdiaper have still not been joined for forming the waist opening and theleg opening, and in which the elastic elements in the pant diaper are intheir stretched-out state;

FIG. 2 shows a section along the line II--II in FIG. 1;

FIG. 3 shows a section along the line III--III in FIG. 1;

FIG. 4 shows a view from the front of the pant diaper in its assembledstate;

FIG. 5 shows a pant diaper according to the invention with the hot-meltmaterial laid out in a spiral shape; and

FIG. 6 shows the invention embodied in a pair of disposable menstrualbriefs.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 thus shows an absorbent pant diaper in its still non-assembledstate, i.e. the waist and leg openings of the diaper have still not beenformed. The pant diaper comprises a front portion 1, intended to beapplied to the front of a user, a back portion 2, intended to be appliedto the rear of the user, and a crotch portion 3 between the front andrear portions 1, 2 intended to be applied between the legs of the user.The front and back portions 1 and 2 also each have two side edges 4, 5intended to be attached together to form a pant diaper according to FIG.4. The pant diaper further comprises an absorbent body 14 extending inthe longitudinal direction of the diaper and which is enclosed betweenan inner cover layer 15 and an outer cover layer 16. The inner coverlayer 15 is applied on the wetting side of the absorbent body 14 facingthe user. It is liquid-permeable and consists, for example, of fibrefabric, a so-called non-woven. The outer cover layer 16 isliquid-impermeable or at least hydrophobic and can, for example, consistof a layer of polyethylene or a fibre fabric which has been coated orlaminated with polyolefines, for example, so that it is madeliquid-impermeable or at least hydrophobic. The absorbent body 14 can,for example, comprise cellulose fibres as absorbent material.Furthermore, it can comprise other absorbent materials such as polymerhydrocolloid materials, for example in particle form.

Such materials are usually called super-absorbents defined as materialswith a capacity to absorb liquid many times its own weight. A pluralityof transverse elastic elements 17, for example elastic threads, tapes orthe like, are applied in a pretensioned state across both the front andback portions 1, 2. The required number of such elastic threads is,however, less here than in previously known pant diapers with the samestay-up capacity.

In the front and back portions 1 and 2, respectively, layers 27 and 28,respectively, of textile-like material, for example fiber fabric, arearranged on the outermost layer of the pant diaper. The elastic threads17 are applied between these layers 27, 28, and the outer cover layer 16or the inner cover layer 15, respectively, within those portions of thefront or back portion in which the outer cover layer 16 does not extend.

The rear layer 28, as does the front layer 27, extends somewhat in overthe rear or front edge of the absorbent body, thus also covering aportion of the outer cover layer 16. Along the front and back waistportions of the pant diaper, there extend two elastic elements 33, whichcan consist of elastic threads, tapes or the like applied pretensionedand which in this embodiment have a greater contractive force than theindividual elastic elements 17 described above.

According to the invention, the surface 15 of the waist portion facingthe user has portions 6a-d of a friction agent in order to increase thefriction against the skin and thus prevent the pant diaper from slippingdown.

The friction agent can be, for example, a flexible material of hot-melttype, i.e. a fusible glue, which provides a coating with a surface whichis smooth and non-porous. It must, however, not stick fast to the skinof the user, even at such high temperatures as 50° C. Flexible in thiscontext means that the material is compliant and thus can follow and bestretched to the same extent as the material in the waist of the pantdiaper when it is stretched as the user moves.

A suitable hot-melt material for use in this context is a material basedon thermoplastic rubber, for example styrene isoprene rubber (SIS),styrene butadiene rubber (SBR), or styrene ethylene butadiene styrenerubber (SEBS). Other hot-melt materials can also be used, for examplewithin the following groups: ethylene vinyl acetate copolymers,cellulose acetate butyrate, ethyl cellulose, and acrylic materials.

Other examples of friction agents are material of foam-type andwater-based materials, for example polyvinyl acetate.

Portions 6a-d applied at the hip portions but not over the seams betweenthe edge portions 4, 5 and not directly in the centre of the front andback portions have proved to be advantageous since the hands are placedthere when pulling the pant diaper on and off. But the elastic hot-meltmaterial can, of course, be applied in a strip or string extendingaround the entire inside of the waist portion, but this can, however,mean that certain portions of the hot-melt strip will stick to thestomach or backside when the pant diaper is pulled on or off. Thehot-melt material can also be applied in the form of drops of glue or inspiral patterns which have been sprayed on various areas around thewaist. One example of such an alternative application of hot-meltadhesive is shown in FIG. 5, where the material has been applied by aspray nozzle in a spiral form extending in a strip around the entirewaist portion.

It is thus possible with the present invention to make the elasticthreads 17 and/or 33 with less tension or fewer number and at the sametime achieve the same stay-up capacity with better wearer comfort. Inorder to achieve the same wearer comfort without the present invention,it would have been necessary to provide pant diapers with many differentwaist sizes, and this would make the product much more expensive andmore difficult to use for the consumer.

FIG. 6 shows the invention embodied in a pair of menstrual briefs wherecorrespondingly labeled strips of hot-melt friction increasing material6a-d have been applied around the elasticized waist portion of a pair ofmenstrual briefs to achieve the same advantages as regards comfort andholding up capacity as are achieved in the pant diaper example discussedabove.

The menstrual briefs are also provided with friction increasing hot-meltpatches 19 along the leg openings facing the buttocks. They prevent theedges of the leg openings in the rear of the briefs from sliding acrossthe buttocks and into the crease between the buttocks, causingdiscomfort and bunching of the absorbent material.

The invention claimed is:
 1. Disposable absorbent pant, comprising acrotch portion, front and back portions adjacent thereto which arejoined to form a waist portion of the disposable absorbent pant forsurrounding the waist of a user, said waist portion beingcircumferentially elastic, at least one cover layer extending from atleast said front portion to said back portion, an absorbent bodydisposed adjacent to said at least one cover layer, said absorbent bodybeing held tightly against the body of the user by the elastic waistportion, wherein at least portions of the surface of the waist portionfacing the skin of the user are provided with skin engagement means forincreasing friction against the skin, relative to the surface of saidwaist portion, and thereby creating frictional resistance with the skin.2. Disposable absorbent pant according to claim 1, wherein the frictionagent is flexible and compliant with the elastic waist portion. 3.Disposable absorbent pant according to claim 1, wherein the skinengagement means for increasing friction includes a hot-melt material.4. Disposable absorbent pant according to claim 3, wherein the hot-meltmaterial is based on a thermoplastic rubber.
 5. Disposable absorbentpant according to claim 1, wherein the friction agent consists of awater-based material.
 6. Disposable absorbent pant according to claim 1,wherein the friction agent consists of a material of foam-type. 7.Disposable absorbent pant according to claim 1, wherein the frictionagent is arranged in portions extending in a row around the entireinside of the waist portion.
 8. Disposable absorbent pant according toclaim 1, wherein the waist portion includes a right hip portion and aleft hip portion, the friction agent being arranged in portions whichonly extend along the right and left hip portions of the waist portion.9. Disposable absorbent pant according to claim 1, wherein the frictionagent extends in a continuous strip along the waist portion. 10.Disposable absorbent pant according to claim 1, wherein the frictionagent is arranged in the form of points on the inside of the waistportion.
 11. A disposable absorbent diaper comprising:a crotch portion;front and back portions adjacent to the crotch portion which are joinedtogether to form a waist portion of the disposable absorbent diaper forsurrounding the waist of a user, said waist portion beingcircumferentially elastic; at least one cover layer extending from atleast said front portion to said back portion; and an absorbent bodydisposed adjacent to said at least one cover layer, said absorbent bodybeing held tightly against the body of the user by the elastic waistportion; wherein at least portions of the surface of the waist portionfacing the skin of the user are provided with skin engagement means forincreasing friction against the skin of the user, relative to thesurface of said waist portion, and thereby creating frictionalresistance with the skin.
 12. Disposable absorbent pant according toclaim 1, wherein the absorbent body is connected to said at least onecover layer.
 13. Disposable absorbent pant according to claim 1, whereinsaid at least one cover layer includes two cover layers and theabsorbent body is enclosed between the two cover layers.
 14. Disposableabsorbent diaper according to claim 11, wherein the absorbent body isconnected to said at least one cover layer.
 15. Disposable absorbentdiaper according to claim 11, wherein said at least one cover layerincludes two cover layers and the absorbent body is enclosed between thetwo cover layers.
 16. Disposable absorbent pant, comprising a crotchportion, front and back portions adjacent thereto which are joined toform a waist portion for surrounding the waist of a user of thedisposable absorbent pant, said waist portion being circumferentiallyelastic, at least one cover layer extending from at least said frontportion to said back portion, an absorbent body disposed adjacent tosaid at least one cover layer, said absorbent body being held tightlyagainst the body of the user by the elastic waist portion, wherein atleast portions of the surface of the waist portion facing the skin ofthe user are provided with skin engagement means for increasing frictionagainst the skin, relative to the surface of said waist portion, saidskin engagement means providing smooth contact surfaces for contactingthe skin of the user and creating a frictional resistance therewith.